AV Amplifier

Abstract

When a first bi-wiring speaker is connected to output terminals 5A and 5B and a second bi-wiring speaker is connected to output terminals 5D and 5E, and further a two-channel stereo reproduction is performed, a signal 3L for a L channel outputted from a decoder 2 is amplified by amplifiers 4A and 4B in parallel to be given to the first bi-wiring speaker in a bi-wiring connecting manner and a signal 3R for a R channel outputted from the decoder 2 is amplified by amplifiers 4C and 4D in parallel and given to the second bi-wiring speaker in a bi-wiring connecting manner. At this time, a gain corrector 7 equalizes a gain which an output signal of the amplifier 4A has with respect to the signal 3L for the L channel with a gain which an output signal of the amplifier 4B has with respect to the signal 3L for the L channel. Similarly, a gain corrector 8 equalizes a gain which an output signal of the amplifier 4C has with respect to the signal 3R for the R channel with a gain which an output signal of the amplifier 4D has with respect to the signal 3R for the R channel.

What is claimed is: 
     
       1. An AV amplifier capable of selectively switching between a multichannel reproducing mode and a two-channel stereo reproducing mode, comprising: a decoder operable to decode input signals in which multichannel signals are encoded to output multichannel signals in the multichannel reproducing mode, and operable to output inputted two-channel stereo signals as they are in the two-channel stereo reproducing mode;   a plurality of amplifiers operable to amplify output signals of said decoder;   a plurality of output terminals to each of which speakers are connected, and which are operable to transfer output signals of said amplifiers to the connected speakers;   a mode selector operable to select either the multichannel reproducing mode or the two-channel stereo reproducing mode; and   a switching circuit operable to switch a connected relation among said decoder, said plurality of amplifiers and said plurality of output terminals in accordance with the mode selection by said mode selector, wherein:   said plurality of amplifiers comprises at least first to fourth amplifiers operable to amplify the multichannel signals in the multichannel reproducing mode; and   said switching circuit:   when a plurality of speakers for multichannel reproduction are connected to said output terminals and the multichannel reproducing mode is selected, switches the connected relation so that the multichannel signals outputted from said decoder are amplified by said plurality of amplifiers for each channel and the signal outputted from each of the amplifiers is given to the speaker of a corresponding channel; and   when a pair of speakers compatible with bi-wiring are connected to said output terminals and the two-channel stereo reproducing mode is selected, switches the connected relation so that among the two-channel stereo signals outputted from said decoder, signals for an L channel are amplified in parallel by said first and second amplifiers in said plurality of amplifiers and signals for an R channel are amplified in parallel by said third and fourth amplifiers in said plurality of amplifiers, and further output signals of said first and second amplifiers are given to one of said pair of speakers in a bi-wiring connection manner and output signals of said third and fourth amplifiers are given to the other one of said pair of speakers in the bi-wiring connection manner.   
     
     
       2. The AV amplifier according to claim 1, further comprising: a first gain corrector operable to correct a difference between gains of said first and second amplifiers; and   a second gain corrector operable to correct a difference between gains of said third and fourth amplifiers;   wherein said switching circuit switches the connected relation so that said first and second gain correctors are activated when said pair of speakers compatible with bi-wiring are connected to said output terminals and the two-channel stereo reproducing mode is selected.   
     
     
       3. The AV amplifier according to claim 2, wherein said first gain corrector is operable to correct gains so that a gain which an output signal of said first amplifier has with respect to the signal for the L channel is nearly equal to a gain which an output signal of said second amplifier has with respect to the signal for the L channel; and   said second gain corrector is operable to correct gains so that a gain which an output signal of said third amplifier has with respect to the signal for the R channel is nearly equal to a gain which an output signal of said fourth amplifier has with respect to the signal for the R channel.   
     
     
       4. The AV amplifier according to claim 3, wherein said first and second gain correctors include a fine adjusting device operable to finely adjust the gain correcting amounts. 
     
     
       5. The AV amplifier according to claim 1, wherein: said switching circuit comprises:   a plurality of switches placed among said decoder, said plurality of amplifiers and said plurality of output terminals as necessary; and   a computer unit operable to control on/off states of each of said switches in accordance with the mode selection by said mode selector.